Rotary drill bit of the flat-blade type



April 3, 1928. 1,664,528 c. E. REED ROTARY DRILL BITl oF THE FLAT BLADE TYPE Filed, Nom-5.' 1925 2 Smets-Sheet l INVENTOR.

April 3, 1928.

C. E. REED ROTARY DRILL BIT oF THE, FLAT BLADE TYPE Filed NDV. 5. 1925 2 Sheets-Sheet 2 INVENTOR.

Patented Apr. 3, 1928.

*UNITED STATES PATENTI- OFFICE..

@LAE-.ENCE REED, OF WICHITA, KAETSAS.

. ROTARY DRILL --BIT or THE FLAT-BLADE TYPE.

Appneation aied'n'ove'mter 5, 1925. serial No. 67,001.

This invention relates to rot-ary drill bits,

employed in the art,so as to retain all the.

time tried and proven advantages of the flat blade y1n drilling so ca-lled1`sott earth formations, but combine with such time proven advantages a `means of replacing the worn cutting edge wit-hout the heavy waste necessitated bythe present universal practice ot discarding as scrap the body and threaded shank portions of the usual fish tail bit-s.

Numerous efforts have been made to supply detachable cutting points tor fish tail, and substitute forms of bits, but in every known form there is some inherent weakness culminating always in loosened parts and loss thereof in the well. These parts, always be ing` the hardest steel that is known to the art, and et relative small shape and volume, cause expensive lishing jobs, when they can be recovered at all, and at all times endanger the entire investment in the well. In the case otpresent day deep wells, such investments are seldom less than $25,000.00 and usually more, up to $100,000.00 or over in a single well.

The object of my invention is to provide such forms and combination of elements Vas will retain proven advantages, but secure these advantages in an assembly, the wearing parts of which may be replaced at will at small cost, and so lock theI parts together that to all practical purpose such complete assembly will be as though one solid integral piece. Heretotore, efforts in a similar direction have taught the use of relatively short length cutting elements, and relatively short length portions of the cutting elements penetrating the holder member, or where variations were attempted the resulting structure lacked strength and could not be made stronger because if enlarged wouldL eliminate some other prime essential of an operable structure, as for instance enlarging the cutting element would weaken the holder, or render worthless the retaining means known or prevent circulation of Huid to the bottom, without which a rotary bit could not be safely introduced into any well.

The invention herein disclosed consists in the new combination and arrangement of elements, in part, and the construction hereinafter described and claimed and illustrated in the drawings, in which:

Fig. l, a flat side view ot a blade (8) with taperedv bearing area (7), and cylindrical anchor .section (7a). l l Fig. 2, a side viewl'of the same, showing wedge shaped bearing (9), cutting edge and shank.

Fig. 3, plan view of blade looking down on the shank.

Fig. 4 is a view of a complete tool, `halt the view in section.

Fig. Y5 is a View at `right angles to the view of Fig. 4. f Fig. 6 1s a plan view looking down on the y shank of Fig. 4. Fig.y 7 is a section through Fig. 1 on the line A-A. l

The improved lrotary drill bit comprises anupper portion consisting of a body (l) ot the usual lish tail -bit form, with a.

threaded shank forV attaching to a hollow drill stem. The middle portion of the flat body is thickened'by swelling out the flat sidesito a shortradius. The lower end of the body is iinished with a tapered central socket (2) for a given depth, beyond which the bore is cylindrical (3) and of a diameter same as determined for the small end of the tapered bore. A slot (4) is formed through the body and cylindrical bore at right angles tothe longitudinal axis of the bit, and parallelv to the broad flat sides of. the body. The ends of the slots are cylin.

drical and threaded. Screw threaded plugs (5) are placed in the ends of the slot and Vtightened against the ends of the wedges (6). 'These plugs act as screw jacks to cause the wedges operating through (7b) to draw the taper shank (7) of cutting element (8) to rigid seat in the socket (2) the cylindrical part of shank (7a) centering, but primarily `serving to anchor rigidly the cutting element (8) in thebody (.1). VThe stresses set up in all bits of this species tend to pull the shank of the cutter out of the holder. This invention provides a long shank with a .rigid anchoring section, a.

large bearing portion (the tapered socket (2)) to take all thrusts of loads imposed,

and the wedge (6) draw-in construction holds the cutter and body together as rigidly as if integral. There are no torque or driving stresses von the shank (7) or tapered socket (2). f Just below the tapered portion ofthe shank of the cutter elementV the top or" the blade portion is finished to an inclined bevel or wedge shape (9) sloping upwardly, and inwardly andthe construction lits a correspondingly shaped groove (l) in the lower end face ot the body (l). The draw-in construction- (f-j-Te-Q) of the shank clamps the wedge shaped top (9) of the blade in the groove (l0) of lower end face of body Y(l). The overhanging walls (11') ot the groove (10) drive" the cutter and take all the torque. All the stresses are calculated to carry into the central heavy portion of the cutter element (8) and this is well within and securely anchored' within the body by the bearing. areaot the combined grooi'fes' (10) tapered socket (2) cylin drical bore and draw-in construction.

The usual passageways for fluid circulation are provided and indicated at l2. Means are provided at 13 whereby cutter can be driven out when desired..

I claim:

l. In combination in a rotary deep well drilling tool of lish tail type, a main body of flat iish tail form provided with a shank at its upper end for attachment to a drill stem, said iiat body having an axial socket` in its lower end consisting of an upper cylindrical portion, an'interinediate rustoconical thrust-sustaini'ngv portion tapering upwardly, and colnmunica-ting at its upper end with the lower end of the cylindrical portion, and' a lower beveledl wedge-shaped portion tapering upwardly into communication with the lower end of the frusto-conical portion and extending flatwise across thelower end of the body to form a terminal wedwe-shaped cutter receiving groove therein, a iiat tapered and beveled cutter'blade in said socket and groove having a shank with a cylindrical upper part, and a rustoconi-'cal lower part all to tit vthesaid socket Yand groove, and means for drawing "the shank withY its blade into said body to seat them rigidly in the body', the walls oi' said groove overhangingthe blade so as to take the torque.

2. Apparatus accordingf to claim l, in which said body has a slot formed therethrough at the said upper cylindrical p'or-V body slot and the shank slot having their greater dimension Aparallel with the tool azi-is', yapair ot cooperating` wedges' in said'V aligning slots, and screw plugs in the"y threaded ends oi the slot adapted to act as screw jacks to cause the wedges to draw the tapered shank and cutter blade to a rigidV seat in the body. v

In testimony whereof, I aliix my signature.

CLARENCEE. REED. 

